In 78 AD, Zhang Heng was born in Nanyang, Henan. Being a celebrity, we like to see if the local feng shui is very good. Nanyang is really an outstanding place. Zhuge Liang, a wise sage, and Zhang Zhongjing, a medical sage, were born, so Zhang Heng was called "Zhi Sheng" by local people.
When Zhang Heng was young, he was also a charming man, who liked to travel and love literature. Most of his interests are still in poetry, words and prose. The famous Erjing Fu and Gui Tian Fu are also masterpieces of Han Fu, and Zhang Heng was a great writer in the literary world at that time.
After entering middle age, Zhang Heng gradually turned his attention to astronomy, machinery and calendar. Lingxian is Zhang Heng's masterpiece of astronomy. Zhang Heng pointed out that there are 2,500 stars that can be seen in the Central Plains, and it has been confirmed that they are really close to the number known today.
After observing the movement of some celestial bodies, Zhang Heng came to the conclusion that a day in a week is 365 degrees and a quarter degrees, which is almost the same as the modern measured value that the earth orbits the sun for 365 days, 5 hours, 48 minutes and 46 seconds. This ability to observe gods is amazing. You know, this is the Eastern Han Dynasty 1900 years ago!
The most famous and frequently mentioned is his seismograph. He successfully predicted the Longxi earthquake thousands of miles away from Luoyang by using the seismograph. Abroad, it can be predicted that the earthquake will occur after19th century. It can be said that Zhang Heng's seismograph has surpassed the development of world science and technology for about 1800 years.